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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/*
* This module is in charge of preloading 'new tab' pages for use when
* the user opens a new tab.
*/
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
});
export let NewTabPagePreloading = {
// Maximum number of instances of a given page we'll preload at any time.
// Because we preload about:newtab for normal windows, and about:privatebrowsing
// for private ones, we could have 3 of each.
MAX_COUNT: 3,
// How many preloaded tabs we have, across all windows, for the private and non-private
// case:
browserCounts: {
normal: 0,
private: 0,
},
get enabled() {
return (
this.prefEnabled &&
this.newTabEnabled &&
!lazy.AboutNewTab.newTabURLOverridden
);
},
/**
* Create a browser in the right process type.
*/
_createBrowser(win) {
const {
gBrowser,
gMultiProcessBrowser,
gFissionBrowser,
BROWSER_NEW_TAB_URL,
} = win;
let oa = lazy.E10SUtils.predictOriginAttributes({ window: win });
let remoteType = lazy.E10SUtils.getRemoteTypeForURI(
BROWSER_NEW_TAB_URL,
gMultiProcessBrowser,
gFissionBrowser,
lazy.E10SUtils.DEFAULT_REMOTE_TYPE,
null,
oa
);
let browser = gBrowser.createBrowser({
isPreloadBrowser: true,
remoteType,
});
gBrowser.preloadedBrowser = browser;
let panel = gBrowser.getPanel(browser);
gBrowser.tabpanels.appendChild(panel);
return browser;
},
/**
* Move the contents of a preload browser across to a different window.
*/
_adoptBrowserFromOtherWindow(window) {
let winPrivate = lazy.PrivateBrowsingUtils.isWindowPrivate(window);
// Grab the least-recently-focused window with a preloaded browser:
let oldWin = lazy.BrowserWindowTracker.orderedWindows
.filter(w => {
return (
winPrivate == lazy.PrivateBrowsingUtils.isWindowPrivate(w) &&
w.gBrowser &&
w.gBrowser.preloadedBrowser
);
})
.pop();
if (!oldWin) {
return null;
}
// Don't call getPreloadedBrowser because it'll consume the browser:
let oldBrowser = oldWin.gBrowser.preloadedBrowser;
oldWin.gBrowser.preloadedBrowser = null;
let newBrowser = this._createBrowser(window);
oldBrowser.swapBrowsers(newBrowser);
newBrowser.permanentKey = oldBrowser.permanentKey;
oldWin.gBrowser.getPanel(oldBrowser).remove();
return newBrowser;
},
maybeCreatePreloadedBrowser(window) {
// If we're not enabled, have already got one, are in a popup window, or the
// window is minimized / occluded, don't bother creating a preload browser -
// there's no point.
if (
!this.enabled ||
window.gBrowser.preloadedBrowser ||
!window.toolbar.visible ||
window.document.hidden
) {
return;
}
// Don't bother creating a preload browser if we're not in the top set of windows:
let windowPrivate = lazy.PrivateBrowsingUtils.isWindowPrivate(window);
let countKey = windowPrivate ? "private" : "normal";
let topWindows = lazy.BrowserWindowTracker.orderedWindows.filter(
w => lazy.PrivateBrowsingUtils.isWindowPrivate(w) == windowPrivate
);
if (topWindows.indexOf(window) >= this.MAX_COUNT) {
return;
}
// If we're in the top set of windows, and we already have enough preloaded
// tabs, don't create yet another one, just steal an existing one:
if (this.browserCounts[countKey] >= this.MAX_COUNT) {
let browser = this._adoptBrowserFromOtherWindow(window);
// We can potentially get null here if we couldn't actually find another
// browser to adopt from. This can be the case when there's a mix of
// private and non-private windows, for instance.
if (browser) {
return;
}
}
let browser = this._createBrowser(window);
browser.loadURI(Services.io.newURI(window.BROWSER_NEW_TAB_URL), {
triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
});
browser.docShellIsActive = false;
browser._urlbarFocused = true;
// Make sure the preloaded browser is loaded with desired zoom level
let tabURI = Services.io.newURI(window.BROWSER_NEW_TAB_URL);
window.FullZoom.onLocationChange(tabURI, false, browser);
this.browserCounts[countKey]++;
},
getPreloadedBrowser(window) {
if (!this.enabled) {
return null;
}
// The preloaded browser might be null.
let browser = window.gBrowser.preloadedBrowser;
// Consume the browser.
window.gBrowser.preloadedBrowser = null;
// Attach the nsIFormFillController now that we know the browser
// will be used. If we do that before and the preloaded browser
// won't be consumed until shutdown then we leak a docShell.
// Also, we do not need to take care of attaching nsIFormFillControllers
// in the case that the browser is remote, as remote browsers take
// care of that themselves.
if (browser) {
let countKey = lazy.PrivateBrowsingUtils.isWindowPrivate(window)
? "private"
: "normal";
this.browserCounts[countKey]--;
browser.removeAttribute("preloadedState");
browser.setAttribute("autocompletepopup", "PopupAutoComplete");
}
return browser;
},
removePreloadedBrowser(window) {
let browser = this.getPreloadedBrowser(window);
if (browser) {
window.gBrowser.getPanel(browser).remove();
}
},
};
XPCOMUtils.defineLazyPreferenceGetter(
NewTabPagePreloading,
"prefEnabled",
"browser.newtab.preload",
true
);
XPCOMUtils.defineLazyPreferenceGetter(
NewTabPagePreloading,
"newTabEnabled",
"browser.newtabpage.enabled",
true
);